The snowmaking technology relies on the laws of physics regarding the fact that the boiling point of water changes with the surrounding pressure. Basically, for the snowmaking process a vacuum pressure corresponding to the boiling point of water at a temperature below 0° C. produces water vapor that absorbs the latent heat of vaporization from the water. The water temperature drops until it freezes and reaches the super cooling temperature that corresponds to the existing vacuum pressure.
The technique of freezing water under vacuum pressure has been well established in different industrial areas, such as for cooling and freeze drying applications. There are, however, presently only two existing commercial facilities/systems that produce snow using this technique. The existing systems produce an ice slurry that is pumped in a loop. From said ice slurry loop water is removed to produce snow. A major problem with the above discussed systems is that they require an anti-freezing protection in the ice slurry loop. The used anti-freeze protection is normally in the form of glycol or a NaCl solution, which in both cases are partially discharged with the snow and thereby pollute the environment. The second problem is that you can only produce wet snow with practically no possibilities to control the quality of the produced snow.
Basic systems for producing ice particles or snow using a vacuum technique as described above are disclosed e.g. in U.S. Pat. No. 6,038,869, WO8203679 and WO-2006090387. These systems produce an ice slurry from which the water is or can be removed later in the process depending upon the intended use for the produced ice slurry. When water is removed the snow is still wet, resembling “spring snow” having a high density. Using such methods for making snow, it is thus not possible to control the snow quality and there is also an above mentioned need for an environmentally unfriendly anti-freezing protection in the ice slurry loop.